Mock Questions Flashcards
Are minor salivary glands encapsulated in connective tissue?
No
Describe the embryological development of the midgut
Rotates around the axis of the developing superior mesenteric artery
How much of total saliva production comes from the parotid glands?
~20%
Is acinar cell secretion hyper or hypotonic to plasma?
Hypotonic (due to reabsorption of NaCl)
Why do cystic fibrosis patients suffer from impaired fat digestion?
Cannot secrete bicarbonate ions - reduces effectiveness of digestive enzymes
Where is gastrin secreted from?
G cells lining stomach and upper small intestine
What are the actions of gastrin?
Stimulates stomach to release gastric acid, gallbladder to empty store of bile and pancreas to secret pancreatic enzymes. Also increases stomach motility
How do NSAIDs induce poetic ulceration?
Inhibit synthesis of cytoprotective-prostaglandins
What pharmacological treatment is used for IBS?
Tricyclic antidepressants (amitriptyline)
What is Zollinger-Ellison syndrome?
Gastrin secreting tumour of G cells resulting in peptic ulcers
A construction worker presents with profuse vomiting two hours after buying and eating a sandwich from a catering van. Which organism is most likely to be responsible for his symptoms?
Staphylococcus aureus - enterotoxin with rapid effect when ingested
Why intravenous antibiotics less effective for treatment of Clostridium difficile disease than oral antibiotics?
Oral antibiotics more effective as higher concentrations achieved in gut lumen
Which hepatitis virus contains a DNA genome?
Hepatitis B
Describe cholecystokinin?
Release stimulated by fat in duodenum.
Stimulates contractions of gallbladder and common bile duct - delivery of bile to gut
Describe secretin
Secreted in response to acid in duodenum.
Stimulates biliary duct cells to secrete bicarbonate and water - expands bile volume and increases outflow into intestine
Describe phase I of drug metabolism
Involves cytochrome P450-dependent mono-oxygenases
What is the recommended paracetamol dose?
What is defined as an overdose?
4g in 24 hours (or 75mg/kg)
Overdose = >4g (or >75mg/kg) in a period of <1 hour
How does paracetamol poisoning cause liver damage?
Through one of its metabolites (NAPQI)
What is the effect of dietary fibre on colonic transit time?
Speeds up transit time
What does dietary fibre cause in the large intestine?
Production of short-chain fatty acids
Describe the epithelium in the DCT, CD and ureter
Cuboidal epithelial cells with no microvilli
Is there any protein reabsorption in the kidney?
Yes in the proximal tubule (very little filtered but all reabsorbed by pinocytosis)
Which region of the nephron is relatively hypoxic?
The bottom of the loop of Henle
Where in the nephron is the tubular fluid isotonic to plasma?
Proximal tubule
Where in the nephron does the bulk reabsorption of K+ take place?
Proximal tubule
Is the fluid at the end of the thick ascending limb of the loop of Henle hypo or hypertonic?
Hypotonic
How long does it take for plasma bicarbonate levels to rise in response to acidosis?
A few days due to induction of the ammonium mechanism
What are the contraindications between furosemide and digoxin?
Furosemide can cause hypokalemia and low K+ can increase digoxin toxicity
Why is gout a reason to avoid using thiazide diuretics?
Because they can lead to an increased plasma urate
What is the embryological origin of the parathyroid glands?
The pouch of the 3rd and 4th pharyngeal arch
What nerve leads to sympathetic inner action of the pancreatic islets?
Thoracic splanchnic nerves
What is the relationship between prolactin and GnRH?
Prolactin inhibits hypothalamic GnRH
In starvation, what is the fate of T4?
Conversion to rT3 rather than T3 to reduce metabolism and conserve resources
Where is calcitonin secreted?
What is its effect?
Parafollicular C cells
Lowers plasma calcium
Where is parathyroid hormone secreted?
What is its effect?
Parathyroid chief cells
Increase plasma calcium levels
Why can diabetes mellitus be secondary to development of acromegaly?
Elevated GH can lead to impaired glucose homeostasis and diabetes
How does a hyper-secreting adrenal medulla tumour lead to diabetes?
Adrenaline released, raising blood glucose
What are somatotrophs?
Cells of anterior pituitary that produce GH
What is the relationship between cortisol and glycogen?
Cortisol expands glycogen stores (in prolonged stress) and causes gluconeogenesis
How long do anti-thyroid drugs take to have an effect?
Several weeks due to large stores of TH in thyroid gland
How would you diagnose Addison’s disease?
Lack of response to Synacthen (synthetic ACTH) test. Confirms adrenal hyposecretion
What is the effect of activating the glucagon receptor?
Increased intracellular cAMP
Where are spermatogonia found?
Seminiferous tubules
Where does lymph drainage from the medial part of the tongue body go?
Inferior deep cervical lymph nodes
Give 3 things that increase gastric acid secretion
Activation of vagus nerve
Action of ACh on enterochromaffin-like cells
Presence of food in mouth
Where is the majority of protein digested?
Stomach
Describe the autocatabolistic effect of trypsin
Trypsin acts on trypsinogen to generate more trypsin for proteolysis
What increases intestinal motility?
Muscarinic receptor activation by ACh
Increased stretch of small intestinal smooth muscles
What is hepatic encephalopathy?
Damage to the brain from chronic liver failure
How does oral rehydration therapy for diarrhoea work?
Glucose present promotes sodium absorption via a symporter
What provides symptomatic relief in diarrhoea management?
Opioid receptor agonist (loperamide)
What are the side effects of tricyclic antidepressants such as amitriptyline?
Constipation due to anti-muscarinic side effects
What is first pass metabolism?
Removal of the drug before it enters systemic circulation
What do different isoforms of cytochrome P450-dependent mono oxygenases show?
Significant genetic variation
How does reduced cardiac output lead to oedema?
Reduced blood volume is detected and fluid retention occurs
What is the process of release of TSH from anterior pituitary?
Exocytisis
What is the process of movement of colloid into thyroid follicular cell?
Endocytosis
What is the process involved in the release of cortisol form adrenal cortex cells?
Simple diffusion
What is the vascular supply to the pituitary?
Superior and inferior hypophyseal arteries
What does a lack of dietary iodine result in?
Goitre (enlarged thyroid gland) due to reduced TH and less negative feedback of TSH
Why is the thyroid gland enlarged in hypothyroidism?
Lack of TH reduces negative feedback of TSH
What type of nerve fibres innervate the adrenal medulla?
Preganglionic
What hormones act synergistically in the stress response?
GH and cortisol to increase lipolysis
What effect does Cushing’s syndrome have on bones?
Can cause osteoporosis
What is the relationship between Cushing’s syndrome and diabetes?
Cushing’s can lead to diabetes - elevated glucocorticoids lead to impaired glucose homeostasis
What dietary advice should be given to someone with type 2 diabetes?
Dietary cholesterol intake less than 200mg per day
What is the effect of leptin?
Reduction in food intake - appetite suppressant
What is Prader-Willi syndrome?
Genetic condition that causes excessive appetite and overeating leading to obesity
How would you test for GH tumour?
Oral glucose test - suppressed GH release normally so lack of response = positive result
How long into gestation until fetus can synthesise thyroid hormone?
12 weeks
What is the role of Leydig cells?
Secrete testosterone in the presence of LH
What is the average loss of life expectancy in lifelong regular smokers?
10 years
What is the most effective treatment to stop smoking?
Agonist of nicotinic acetylcholine receptor (varenicline)
